Session Initiation Protocol (SIP) is an application-layer control (i.e., signaling) protocol for creating, modifying, and terminating sessions with one or more users. These sessions may include Internet-based telephone calls, multimedia distribution, multimedia conferences, instant messaging conferences, interactive voice response (IVR), automated and manual operator services, automatic call distribution, call routing, etc. SIP invitations or SIP INVITE requests may be used to create sessions and may carry session descriptions that allow participants to agree on a set of compatible media types. SIP may use proxy servers to help route requests to a user's current location, authenticate and authorize users for services, implement provider call-routing policies, and/or provide other features to users. SIP may also provide a registration function that allows users to upload their current locations for use by proxy servers.
Testing of SIP-based systems typically is a manual and time consuming task. For example, a SIP device (e.g., a SIP telephone) may be a computer-based device that participates in call processing within a SIP-based network. Unlike conventional telephones which may be emulated during testing of network functions, SIP telephones fail to provide such emulation.